Bunch adhoc Questions mainly interior

[FAKKY]

So pulling interior out to wipe down and prime and get ready for sound proofing. a few questions

PO had some sort of old mustang type bucket seats in there held down by four bolts. Pretty shot at least in foam and some rust. Might be salvageable (frame) for reupholster but I guess n idea how much that will be and what other options there are that would work. What did you all do - bench seats ?

Seal around firewall. I've plugged most of my holes with a mixtre of welded plugs, harness plugs and some pushout metal plugs. But I can still see a gap around the seam of the internal firewall to external firewall. What did you guys use to seal this properly.

Windshield wipers. Motor and mechanism. Is it just a 12v system - apply 12v to see if works ? How much effort to replace and fix as like everything else on this truck - probably doesn't work well in current state.

Cowell grill on top outside, I want to seal the holes I made from drilling out the pedal/column support. Can you just pull this out via a number of screws ? Would make access from topside easy.

thx